The present invention relates generally to the construction of a shingle for covering the hip, ridge, or rake portion of a roof. In particular, the present invention relates to the construction of a hip, ridge, or rake shingle having a thick, aesthetic appearance and a self-aligning mechanism for the rapid and uniform installation of a number of such shingles.
In the roofing art, it is well-known to attempt to enhance the appearance of a non-wood hip, ridge, or rake shingle by increasing the height of such a shingle to simulate the height of a wood shingle. Examples of such shingles are provided in U.S. Pat. Nos. 5,471,801; 5,377,459; 5,247,771; and 3,913,294. In addition, another example of such a shingle is provided by the Z-Ridge(copyright) shingle product sold by Elk Corporation of Ennis, Tex. These shingles are constructed using creative folding designs for the shingle web material to create an overall shingle appearance that is thicker than that of the web material alone.
While these shingles provide an improved appearance over unfolded or flat shingles, they all suffer from common deficiencies. First, all of the shingles are difficult to align while installing and, thus, require great care in installation to avoid unsightly irregular appearances. Second, when installed, the shingles produce an exaggerated xe2x80x9csaw-toothxe2x80x9d appearance, which is different than the more level appearance of wood shingles. Third, the shingles are difficult (if not impossible, in some cases) to install over xe2x80x9cridge ventxe2x80x9d products (to be discussed below). Moreover, even in the best case, installation is a two-step process: the xe2x80x9cridge ventxe2x80x9d products are nailed in place, followed by the installation of the ridge shingles. Finally, with time and heat, the folds in the shingles tend to compress and the shingles tend to droop and lose their wood-like appearance.
It is an object of the present invention to provide a hip, ridge, or rake shingle that overcomes these deficiencies.
According to the present invention, there is provided a hip, ridge, or rake shingle, which includes a shingle panel and at least one rigid back member. The shingle panel has a substantially planar lower surface and an upper surface. The back member has a length that is substantially the same as or greater than the length of the shingle panel. The back member is attached to the substantially planar lower surface of the shingle panel. The back member includes a step in thickness in a cross-sectional plane perpendicular to the substantially planar lower surface and parallel to the longitudinal axis of the back member. In addition, the thickness of the back member at the high level of the step is greater than the thickness of the back member at one of its ends.
Preferably, the shingle panel is composed of an asphalt material and the upper surface of the shingle panel includes a granular material thereon. Preferably, the composition of the shingle panel further includes a rubberized material. The rubberized material is preferably a styrene-butadiene-styrene block copolymer. Preferably, the back member is composed of an injection-molded thermoplastic. Alternatively, the back member may be composed of any rigid material suitable for outdoor exposure, such as molded recycled tire rubber, metal, or wood. If a thermoplastic is used, the back member may include from about 40% to 70% filler by weight.
Preferably, the back member includes a trapezoid-shaped base and a plurality of walls extending from the base. The step in thickness of the back member is provided by a step in the height of the walls in a cross-sectional plane perpendicular to the base and parallel to the longitudinal axis of the back member.
For installation with xe2x80x9cridge ventxe2x80x9d systems (to be discussed below), the back member preferably includes channels formed therein communicating between a side of the back member and an area near the longitudinal center axis of the shingle panel. Preferably, the channels are formed in a zig-zag or herringbone pattern. Through the channels, the shingle according to the present invention is able to vent the air escaping through the ridge vent of the roof to the outside environment.
In yet another preferred embodiment of the invention, the back member includes a planar base surface that is attached to the substantially planar lower surface of the shingle panel. Opposite the planar base surface, the back member includes a surface inclined with respect to the planar base surface and a surface parallel to the planar base surface. At the juncture between the inclined surface and the parallel surface, there is formed the step in thickness of the back member. In this embodiment, the back member preferably includes cavities formed therein. The cavities lighten the back member, but at the same time do not substantially impair the rigidity of the back member.
According to another aspect of the present invention, the back member is attached to the shingle panel using a novel asphaltic adhesive. The asphaltic adhesive includes from about 62% to about 99% by weight of an asphalt cement; from about 0.5% to about 15% by weight of a first thermoplastic having a glass-transition temperature in the range from about 190xc2x0 F. to about 260xc2x0 F.; and from about 0.5% to about 15% by weight of a second thermoplastic having a glass-transition temperature in the range from about xe2x88x9255xc2x0 F. to about 0xc2x0 F.
The grade of the asphalt cement may be any of the grades specified by the American Society for Testing and Materials in Tables 1 to 3 of Publication D3381-92, entitled xe2x80x9cStandard Specification for Viscosity-Graded Asphalt Cement for Use in Pavement Construction.xe2x80x9d A blend of different grades of asphalt cement may be used.
Preferably, the grade of the asphalt cement is AC-30 or below. In addition, it is preferred that the first thermoplastic is a styrene-butadiene-styrene block copolymer having a butadiene/styrene ratio in the range of about 68/32 to about 84/16, a block polystyrene in the range from about 30% to 32%, and an oil content in the range of from about 4.5 phr to 5.5 phr. It is also preferred that the second thermoplastic is a styrene-isoprene-styrene (SIS) block polymer or a latex having a molecular weight in the range of about 100,000 to about 100 million atomic units. The latex may be of a wide variety, including anionic latex, cationic latex, and a combination thereof. Preferably, the latex comprises a styrene-butadiene rubber polymer having from about 62% to about 70% polymer solids in water, a pH in the range of about 5.25 to about 10.5, and a monomer ratio of butadiene to styrene in the range from about 74/26 to about 78/22.